they never had enough spare energy because their guts were using. when we started eating meat, a much more concentrated form of food it freed up energy and we could start to run a bigger brain. >> stephen: that's why vegetarianism seems tow stupid to me. > thank you so much for joining me. the book is "lone survivors." chris stringer. we'll be right back. ( cheers and applause ) ( cheers and applause ) >> stephen: oh, hi there. i was just waiting for the camera to come back on and give my life meaning. ( laughter ) last month, we celebrated the seventh anniversary of the "colbert report." i didn't mention it at the time because america was thoughtlessly holding its presidential campaign during my special day. you know, i've been thinking about the last seven years, 1,118 shows, and asking what were our triumphs? what were our failures? when was the last time i slept? ( laughter ) of course, traditionally the seventh anniversary gift is wool, so i was going to get you sheep, then i thought, no, that's stupid. i've got a better present. i present the